I've always pictured the Weasley twins as having a foxes. I mean, Mr Weasley having a weasel suits him, but I can't imagine Fred and George having weasels somehow. Foxes are absolutely bonkers though, so they work pretty well I think (We have foxes in the park behind our house and they make a HELL of a din when they have cubs!).
The rest of the Weasleys? Well, in my opinion...
Charlie; Dragon (what else?! A small one mind you, perhaps a knucker or a lindworm...)
Molly; Chicken (don't ask me WHY, I suppose she reminds me of Clucky from Robin Hood... plus, have you ever seen an angry chicken?! If not, play Zelda... they're scary
Fred and George; Fox
Plural for patronus; patroni? Maybe? Going with the Latin sort of ending anyway... Patronuses doesn't quite sound right to me >.< The foxes came out a bit more Disney than I'd like, but still, I'm tired, so ner.
Anyway, I'm NOT going to update for a while now. Honest. I know I said I wouldn't yesterday, but, well... um. I'll work on another fairly long comic strip thing now anyway, so I'll be busy. Consider this a thankyou for over 10000 page views! (I know it's way more than that, but seriously... wow).